Starting with GFO/Carbon reactor

[ohioreef71]

I recently got a BRS gfo/carbon reactor to help with some bubble algae popping up. I know they say to start things slow so I only added about 1/4 of the recommend amount to get things going. My total tank volume is about 75g. I used 1/2 cup carbon and 1/4 cup HC gfo It's been about 4 wks should I up the dose? Haven't really noticed a change in the tank yet.I have a mixed reef with lots of sps and a few softies like xenia and star polyps. I read somewhere if I started to quickly with gfo I may wipe out the softies has anyone ever heard of that?

 

[DHyslop]

GFO really won't work well unless you're testing regularly for phosphates.

GFO will adsorb phosphate until it becomes saturated and then start to leech it back into the water. Assuming you have some non-zero amount of phosphate in your water, leaving 1/4 cup in for a month is basically equivalent to not having used any.

Test your phosphates (use one of the Hanna checkers), add a couple cups of GFO and test the next morning. If your first reading was high, you'll likely find a lot less now and it's a good time to swap the media. If your first reading was fairly low, it should read close to zero now and you can keep testing every couple days and change it out when the level starts to creep up again.

Once you get a feel for how much your system uses you won't need to test more than once a week or so and a reactor full of GFO will probably last several weeks in the tank.

Edit: I personally haven't seen any major issues with softies, but you generally do want to avoid big swings. Another good reason to test.